Khan S A, Novick R P
Plasmid. 1983 Nov;10(3):251-9. doi: 10.1016/0147-619x(83)90039-2.
pT181 is a naturally occurring Staphylococcus aureus plasmid, encoding inducible resistance to tetracycline. The plasmid has a copy number of about 20 per cell, and belongs to the incompatibility group inc3. The complete nucleotide sequence of pT181 has been determined and consists of 4437 bp. The nucleotide sequence contains 69.8% A-T and 30.2% G-C pairs. pT181 was found to contain four open reading frames capable of coding for polypeptides containing more than 50 amino acids. All the putative polypeptides are coded by one strand. The molecular weights of the four putative polypeptides are (in daltons): A, 37,500; B, 35,000; C, 23,000, and D, 18,000. Polypeptide A corresponds to the repC protein, earlier shown to be specifically required for pT181 replication. Polypeptide B (and possibly polypeptide D) are involved in tetracycline resistance. No role has yet been established for polypeptide C; deletion of the coding sequence for the C polypeptide has no detectable effect on any property of the pT181 plasmid. A region consisting of about 1200 bp contains information for the replication and copy number control of this plasmid. The sequencing results are discussed in relation to the replication properties and tetracycline resistance associated with the pT181 plasmid.
pT181是一种天然存在的金黄色葡萄球菌质粒，编码对四环素的诱导抗性。该质粒每个细胞的拷贝数约为20，属于不相容群inc3。pT181的完整核苷酸序列已确定，由4437个碱基对组成。核苷酸序列中A-T对占69.8%，G-C对占30.2%。发现pT181含有四个开放阅读框，能够编码含50多个氨基酸的多肽。所有推定的多肽均由一条链编码。这四个推定多肽的分子量（以道尔顿计）分别为：A，37,500；B，35,000；C，23,000；D，18,000。多肽A对应于repC蛋白，先前已证明其是pT181复制所特别需要的。多肽B（可能还有多肽D）与四环素抗性有关。多肽C的作用尚未确定；缺失C多肽的编码序列对pT181质粒的任何特性均无可检测到的影响。一个由约1200个碱基对组成的区域包含该质粒复制和拷贝数控制的信息。结合与pT181质粒相关的复制特性和四环素抗性对测序结果进行了讨论。
